Procedure was the same for Experiment 1 and 2. Tasks were presented in as many sessions as needed over several days in order to minimize the influence of fatigue on performance. Great care was taken to ensure that all participants attended to the different tasks across all trials. There was no time restriction for any test.

Before proper testing, instruction was given. The examiner modelled task execution so that participants knew tasks’ expectations and how to carry out the tests. Two practice items were presented as well.

Tasks were presented in the same order for all participants. The test session began with phonological skill tasks, followed by the Digit Span test, the reading tests, and finally the spelling tests. In order to control any order effect, tasks presentation order was counterbalanced within phonological skills, reading and spelling tasks.

Phonological skills tasks’ stimuli were applied in a visual modality. The examiner, instead of pronouncing the name of the stimuli, presented well-known pictures depicting them. There was no validation of the test items to compare use of pictures and symbols instead of words, but this confounding variable was controlled through the use of familiar words selected from Calero et alt. (1999), and Cuetos et alt. (2000), and familiar pictures. These pictures and words were then contrasted with information provided by parents, teachers and caregivers and through the examiner’s own observation.

Accuracy data were collected for every task. Every response was codified as it follows. In the Digit Span test, one point was computed for every numerical series repeated in the right order. Maximum score was the highest number of numbers repeated in the same order as the examiner presented.

In the phonological skill tasks, one point was computed for every correct response at every task. In the oddity task, one point was given for every odd word identified; final score was total number of correct odd words identified. In the counting syllable task, one point was computed for every word whose syllables were correctly counted; final score was the number of words with correctly counted syllables. In the counting phoneme task, one point was given for every word whose phonemes were correctly counted. In the phoneme identification task, one point was computed for every sound correctly identified in a word; final score was the highest number of correctly identified sounds. Finally, in the phoneme blending task, one point was computed for every picture matched to the sequence of phonemes that the participant correctly blended. All participants’ scores at the phonological skill tasks were added in order to obtain a global phonological skill performance profile.

In the orthographic knowledge test every participant was given one point for every word and non word correctly sorted out in the lexical decision task; maximum score was 30. In the word reading test one point was computed for every word correctly read and then matched with its corresponding pictographic symbol; maximum score was 30. In the pseudoword reading test participants scored one point for every pseudoword they read; maximum score was 20.

In the word spelling task, the number of correct spelled words, the number of total spelled letters and the number of first and final letters in words was calculated. Maximum score was 6 spelled words, 36 spelled letters, 6 first letters spelled and 6 final letters spelled. In the pseudoword and pictures’ names spelling tasks the number of correct spelled pseudowords and pictures’ names, the number of total spelled letters in pseudowords and in pictures’ names, and the number of first and final letters in pseudowords and in pictures’ names were also computed. Same scores were given in the pseudoword and pictures’ name spelling tasks as in the word spelling task.

Results

Data have been processed with SPSS 11.0 (under permission of Siain, University of A Coruña).

Experiment 1

Reading and spelling descriptive data for working memory groups are showed in Table 4. Statistical analyses were made from percentages’ scores.

Table 4:

Reading and spelling descriptive data in working memory capacity groups

Working memory capacity

Low

WM1

High

WM2

N

Mean

Sd

%

Mean

Sd

%

Recognized patterns

6

14.67

7.94

48.9

24.00

7.51

80

Read words

6

17.83

4.75

59.4

22.83

9.23

76.1

Read p seudowords

6

9.00

8.39

45

16.17

3.92

80.8

Nº of spelled words

6

1.50

1.87

25

3.83

2.63

63.8

Nº of spelled pseudowords

6

1.33

1.21

22.1

3.33

2.80

55.5

Nº of spelled pictures' names

6

.83

1.60

13.8

4.00

2.75

66.6

Nº letters spelled in words

6

17.33

11.5

48.1

27.17

13.43

75.4

Nº letters spelled in pseudowords

6

15.00

11.45

41.6

25.17

15.13

69.9

Nº letters spelled in pictures’ names

6

16.50

10.50

45.8

26.50

15.12

73.6

Nº first letters in words

6

3.00

2.53

50

4.83

1.94

80.5

Nº first letters in pseudowords.

6

2.83

2.56

47.1

4.50

2.51

75

Nº first letters in pictures’ names

6

2.67

2.16

44.5

4.50

2.07

75

Nº last letters in words

6

2.83

2.13

47.1

4.33

2.58

72.1

Nº last letters in pseudowords

6

2.83

2.48

47.1

4.17

2.56

69.5

Nº last letters in pictures’ names

6

2.83

2.31

47.1

4.50

2.51

75

There were differences between high (WM2) and low (WM1) working memory capacity groups in descriptive reading and spelling data. WM2 performed better than WM1 in all the reading and spelling tasks (see Table 4 and Figures 1 and 2).

Figure 1.

Reading percentages in working memory and phonological skills groups

Figure 2.

Spelling of lexical elements’ percentages in working memory and phonological skills groups

Reading and spelling descriptive data for phonological skills groups are showed in Table 5. Statistical analyses were made from percentages’ scores.

As it is showed in Table 5 and Figures 1 and 2, high phonological skills group performed better than low phonological skills group. There were differences between PS2 and PS1 in all descriptive reading and spelling measures. However, t-Student analysis only showed statistical significant differences between groups in reading, specifically, in the number of sight words read (t = 3.43; p